Reversible rotary pump



Nov. 3, 1959 A. J. NICHOLAS 2,910,947

REVERSIBLE ROTARY PUMP I Filed May 16, 1957 2 Sheets-Sheet l 26 I] FIG.3 ANDREW J'. NICHOLAS z4- I ---49 I INVENTOR.

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ANDREW J. NICHOLAS INVENTOR. BY 2M 14 1% United States Patent 9 REVERSIBLE ROTARY PUMP Andrew J. Nicholas, Snffield, Cnn., assignor to Worthington Corporation, Harrison, N.J., a corporation of Delaware Application May 16, 1957, Serial No. 659,712

2 Claims. (Cl. 103-117) The present invention relates to a self-priming rotary pump for use with a motor in a hermetically sealed unit or apparatus which pump is adapted to deliver fluid irrespective of the direction of rotation of the motor.

In hermetically sealed vertically mounted refrigeration compressors it is necessary to provide a lubricating pump for the lubrication system therein which will be selfpriming and deliver lubricant under pressure to the main bearings and the eccentrics of the connecting rods when the compressor is in operation.

However, the motor in such applications is generally of the multi-phase type and hence its direction of rotation is indeterminate. Accordingly, if the lubricant pump is connected for operation with such motor it must be constructed so that it will function in either a clockwise or counterclockwise direction of rotation. One pump of this type is shown in U.S. Patent No. 1,035,449 issued August 13, 1912.

Heretofore, because of the complex passageways and valve arrangement utilized in such pumps as is indicated in the above cited patent, the cost of manufacture of pumps for performing this type operation in hermetic units has been relatively high.

The present invention overcomes this problem by providing a rotary pump to be mounted in the fluid sump or reservoir ofa hermetically sealed apparatus which pump includes, a piston chamber formed in the casing thereof, an eccentric piston in the piston chamber adapted to be connected to the motor unit of hermetically sealed apparatus, spaced passage means in the casing for passing fluid from the sump to the piston chamber and from the piston chamber to the point of discharge, and means for sealing the spaced passage-means from each other disposed between the point where the passage-means communicate with the piston chamber including a springbiased plunger which maintains continuous contact with the eccentric piston during its rotation in the piston chamber.

The invention is further characterized by the fact that the passage means are simple and inexpensively formed in the casing of the pump; flow control valves provided in the passage means are of a simple ball type and are accommodated in the valve passage means in a novel and inexpensive manner, and further, means are provided for bypassing fluid back to the inlet side of the pump to relieve excessive pressure.

Accordingly, it is an object of the present invention to provide a simple, inexpensive self-priming rotary pump adapted to operate in either direction of rotation and to deliver fluid at the desired operational pressure.

It is another object to provide a rotary pump which will have flow control means readily accommodated in the passage means thereof.

It is another object to provide pressure sensitive valve means readily accommodated in the passage means, one of which is adapted to divert excess fluid back into the inlet side of the pump.

And it is a still further object to provide a relatively 2,910,947 Patented Nov. 3, 1959 simple and inexpensive means for sealing the main passage means one from the other so that uni-directional flow will occur regardless of the direction of rotation of the pumping piston in the pump.

The invention will be better understood when considered in connection with the accompanying specification and drawings forming a part thereof, in which:

Figure 1 is a view showing the combination of a compressor and a rotary pump, parts thereof being broken away and shown in section.

Figure 2 is an enlarged side view of the pump.

Figure 3 is a top view of the pump.

Figure 4 is a top view of a section of the pump taken on line 44 in Figure 2.

Figure 5 is also a top view of a section of the pump, but taken on line 5-5 in Figure 2.

And Figure 6 is a front view of a section of the pump taken on line 6-& in Figure 2.

THE HERMETICALLY SEALED UNIT Referring to the drawings, Figure 1 shows an hermetically sealed motor driven compressor unit generally designated 1 which is provided with a rotatable shaft 2 centrally disposed therein. A section 3 of the shaft 2 descends below the lower end of the compressor and is received in an axial bore 4 of a rotary pump 5. This pump is connected to the compressor by bolts 6 that are disposed through ears 7 formed on either side of the pump casing 8 and threaded into the lower bearing spider structure 9 of the compressor. The lower portion 16 of the outer casing 11 of the compressor extends beyond the lower end of the pump forming a sump or reservoir 12 which is filled with a suitable lubricating fluid.

The rotary pump 5 has its lower or suction end 13 in continuous communication with the lubricating fluid in the reservoir 12, a strainer 14 being provided about the pump inlet to prevent the inlet from becoming clogged. In the operation of the pump the fluid entering the pump inlet is discharged at the upper or discharge end 15 and is made to flow up along the outer periphery of the shaft Z-through vertical passageways 81 and 82 provided in a bushing element 16 encircling the shaft 2 immediately above the discharge end of the pump. The fluid flowing through these passageways in the bushing element 16 is collected in an annular groove 17 formed in an upstanding cylindrical section 18 of the bearing spider structure 9 and enters in inlet 19 to a passageway 20 extending centrally through the shaft 2. The passageway 20 has suitable outlets 19' communicating with the eccentrics 21 of the connecting rods and the main shaft. bearings 21 through which the lubricating fluid is delivered for lubricating purposes.

THE ROTARY PUMP 1. Structure in general Figures 2, 3, 4, 5 and 6 show the details of construction of the rotary pump 5. Figure 2 shows how the lower shaft extension 3 is disposed in the axial bore 4 of the pump and has an eccentric piston 22 formed on the lower end portion thereof (also see Figure 5). As most clearly shown in Figures 4, 5 and 6, the network of fluid passageways that is formed in the pump casing 8 consists of two vertical and two horizontal bores extending through the pump casing 8. The two vertical bores or main fluid passageways designated 23 and 24 extend from the inlet end 13 to the outlet end 15 of the pump and are disposed on opposite sides of the axial bore 4 which receives the shaft extension 3. The horizontal bores 25 and 26 connect the vertical fluid passageways 23 and 24 in two horizontal planes resulting in four points of intersection as at 27, 28, 29 and 30. The lower horizontal bore 26 in addition tangentially intersects the axial bore 4 in the horizontal plane in which the eccentric piston 22 is formed on the shaft extension 3 and thereby provides an opening 31 through which the vertical fluid passageways 23 and 24 communicate with the compres sion or piston chamber 32 formed about the eccentric piston 22. However, it is necessary to prevent direct communication between the said vertical fluid passageways 23 and 24 through the lower horizontal bore 26, and thus, a sealing means generally designated 33 is provided for this purpose. This sealing means is disposed in a counterbore 34 provided in a hub 35 formed in the pump casing 3 and is adapted to continuously contact the eccentric piston 22 with its inner end 36 to seal the vertical passageways 23 and 24 from each other.

Referring to Figure 6, it is shown that on the lower or inlet side of each of the points of intersection 27-3'0, a suitable ball type valve means generally designated 37 is located in the said vertical fluid passageways to control the flow of fluid in one direction through the rotary pump 5. The ball valve means 37 in the same horizontal plane in each vertical fluid passageway is identical, and taking those in the left vertical fluid passageway 23, they are shown to consist of a large ball 38 seated in a valve seat 39 formed in the upper end of the vertical fluid passageway, and a small ball 40 seated in a valve seat 41 similarly formed in the said vertical fluid passageway but in the lower end thereof. Above, or on the outlet side of the large ball 38, a plug 42 is disposed in the outer end 43 of the upper horizontal bore 25 and has a nib 44 on its inner end extending into the vertical fluid passageway which restricts the large ball 38 to the immediate area above its valve seat 39. A plug 45 having a nib 46 is disposed in the outer end 47 of the lower horizontal bore 26 above the small ball 40 for this same purpose. In the right vertical fluid passageway 24 there are similarly provided balls 48 and 49; valve seats 50 and 51; and plugs 52 and 53 having restraining nibs 54 and 55 respectively.

2. Operation According to the known principle of operation of the rotary pump 5, when the shaft 2 is rotated in the direction of the arrow at on Figure 5, the suction caused by the rotation of the eccentric piston 22 will cause the ball 49 in the valve seat 51 to be moved against nib 55 of plug 53, thus permitting the fluid in the reservoir 12 to pass through this valve seat opening into the chamber 56 of the vertical fluid passageway 24. The rotation of the eccentric piston 22 will cause the fluid to be drawn through the section 57 of the horizontal bore 26 through the opening 31 into the piston chamber 32, and forced through said piston chamber out through the opposite side of the opening 31, through the section 58 of the horizontal bore 26 into the chamber 59 of the vertical fluid passageway 23. This flow of fluid into the left vertical fluid passageway 23 will cause the ball 40 to be moved against its valve seat 41 and effectually prevents the passage of any fluid through the opening of the valve seat 41 back into the reservoir 12. The force of the fluid will however cause the ball 38 in the valve seat 39 to be moved against the nib 44 of plug 42 and open this valve so that the fluid may pass through the outlet opening 61 of the left vertical fluid passageway 23. The fluid thereupon enters a recess or outlet chamber 62 formed in the upper face of the pump through a port 63 connecting the outlet opening 61 with the outlet chamber 62 (see Figure 3). A portion of the fluid discharging through the opening of the upper valve seat 39 will pass through the upper horizontal bore 25 to the upper end of the right vertical fluid passageway 24 causing the ball 48 to be moved against its valve seat 50 to close off this fluid passageway except for the discharge of fluid into the outlet chamber 62 through the outlet opening 65.

In the event that the shaft 2 rotates in the opposite direction, or in the direction of the arrow y, the ball 40 in the left vertical fluid passageway 23 would be 4 T drawn over to the nib 46 of the plug 45 and the fluid entering this fluid passageway would pass through the opening of the valve seat 41 and be forced through the section 58 of the lower horizontal bore 26 into the piston chamber 32. From there, the fluid would pass through the section 57 of the lower horizontal bore 26 into the chamber 56 of the right vertical fluid passageway 24, the pressure therein causing the ball 49 to be forced against its valve seat 51 preventing any return of fluid to the reservoir 12. The fluid entering the right vertical fluid passageway 24, and also entering the left vertical fluid passageway 23 through the upper horizontal bore 25, in turn forces the ball 48 to the nib 54 of plug 52 and the ball 38 to its valve seat 39, thus permitting the fluid to pass into the outlet chamber 62 of the pump from the outlet openings 65 and 62 of the vertical fluid passageways 24 and 23 respectively.

3. Structure in detail As previously indicated, the vertical fluid passageways 23 and 24 consist simply of through bores which are readily formed in the pump casing 8. Further, it is a relatively simple process to form the valve seats 39, 41, 50 and 51 therein. Taking the left vertical fluid passageway 23 for example, first a hole of diameter a is drilled through the pump casing 8; the hole is counterbored with a suitable tool of slightly larger diameter b; and finally the top of the hole is counterbored with a tool of even slightly larger diameter 0. Then, the lower annular end walls of the counterbores are chamfered as at d and e to form the valve seats 39 and 41, respectively. The valve seats 50 and 51 are formed in similar fashion in the right vertical fluid passageway 24.

In the alternative, the pump casing 8 can be fabricated from powdered metal, the vertical fluid passageways 23 and 24, and the valve seats 39, 41, 50 and 51 located therein, being adapted to be die cast.

The plugs restricting the balls to the immediate area above their respective valve seats have been shown to be readily accommodated in the outer ends of the horizontal bores 25 and 26. It is further provided that the two upper plugs 42 and 52 serve as seats for two pressure sensitive valve means generally designated'66, each of which is disposed in the outlet openings 61 and 65 of vertical fluid passageways 23 and 24.

Referring to Figure 6 and taking the pressure sensitive valve means in the left vertical fluid passageway 23, it is shown to consist of a cylindrical cup 67 having an end 68 which seats against the nib 44 of the plug 42, and is biased downwardly against the said nib by a spring or resilient element 69. The resilient element 69 is disposed in the cup 67 and is held in a compressed state by the flat lower surface 70 of the bearing spider 9 when the casing 8 of the rotary pump 5 is bolted in the position shown in Figure l by the cap screws 6. A hole 71 is provided in the end 68 of the cup 67 and acts as a restriction allowing only a predetermined quantity of fluid to pass through at a prescribed fluid pressure. When the fluid pressure exceeds the prescribed value, the cup 67 is forced against the action of the resilient element 69 against the bottom surface 70 of the bearing spider 9. This uncovers an escape port 72 for the excess fluid to flow back into the reservoir 12.

The pressure sensitive valve means in the right vertical fluid passageway 24 consists of a similar cylindrical cup 73 having a constriction opening 74 in its closed end thereof. However, it has not been found necessary to supply a resilient element to this cup or to adapt the cup to divert excess pressure fluid back into the reservoir 12, but it will be understood that this can readily be done.

Referring particularly to Figure 5, the sealing means 33 which seals the vertical fluid passageways 23 and 24 from each other, also consists of a cylindrical cup 75 which is biased by a spring or resilient element 76. This cup however is disposed in the counterbore 34 of the hub 35 formed in the pump casing 8 and is adapted to continuously bear against the eccentric piston 22 under the inward urgency of the resilient element 76. The outer end of the resilient element 76 is seated against a Welsh plug 77 or other similar type element which is expanded in a tight fit in a counterbore 78 in the outer end of the hub 35 thus holding the resilient element 76 in a compressed state. As the cylindrical cup 75 rides against the periphery of the rotating eccentric piston 22 fluid will be drawn into and ejected from the chamber 80 defined by the cylindrical cup 75, counterbore 34, and Welsh plug 77 through an opening 79 which is provided in the Welsh plug 77. In other words, the eccentric piston 22 acts as a rotary cam causing the cylindrical cup 75 to reciprocate in the counterbore 34.

Thus, in the rotary pump 5 which has uni-directional flow of fluid therethrough as herein described, the network of fluid passageways in the pump casing 8 are simply and inexpensively formed of vertical bores 23 and 24, and horizontal bores 25 and 26; the flow control ball valve means 37 are readily accommodated in the fluid passageways; a simple sealing means 33 and pressure sensitive valve means 66 are also readily accommodated in the pump casing 8; and the said sealing means and pressure sensitive valve means are adapted to agitate and thereby cool the fluid in the sump or reservoir 12.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. A rotary pump comprising a casing having an axial bore therethrough, a rotatable shaft disposed in said axial bore and having an eccentric piston formed thereon, a piston chamber defined by said axial bore about said eocentric piston, two vertical fluid passageways bored through said casing, each spaced from said axial bore and on opposite sides of and substantially parallel to a vertical plane passing through the longitudinal axis of said axial bore, two horizontal fluid passageways bored through said casing and intersecting each of said vertical fluid passageways, the lower of said horizontal fluid passageways lying in the same horizontal plane as the eccentric piston and intersecting said axial bore to provide an opening into said piston chamber, means supported said casing and extending into said opening to maintain continuous contact against said eccentric piston to divert fluid flowing through said lower horizontal fluid passageway into said piston chamber, valves disposed in said vertical fluid passageways to regulate flow therethrough in the same direction regardless of the direction of rotation of the shaft, each of said valves being comprised of a ball and valve seat therefor formed in each said vertical fluid passageway below each intersection thereof with each of the horizontal fluid passageways, and a plug disposed in each of the ends of the horizontal fluid passageways and having a nib thereon extending into said vertical fluid passageways to restrict each of the said balls to the immediate area of its said valve seat.

2. That claimed in claim 1 and including a pressure sensitive valve disposed in each of said vertical fluid passageways and seated upon the nibs of said plugs disposed in the ends of the higher of said horizontal fluid passageways.

References Cited in the file of this patent UNITED STATES PATENTS 767,442 Robinson .Aug. 16, 1904 1,035,449 Kinney Aug. 13, 1912 1,600,771 Murphy et a1. Sept. 21, 1926 2,621,593 Schmiel Dec. 16, 1952 FOREIGN PATENTS 626,974 Great Britain July 25, 1949 978,151 France Nov. 22, 1950 

